The present invention relates to a blow molded PET container and in particular to a container with a ribbed base structure to support moderate internal container pressures.
In recent years, PET (polyethylene terephthalate) containers have grown in acceptance by consumers. The primary advantages of PET over glass are the significant weight reduction of the container and its durability and shatter resistance. One major area of use of PET is for carbonated beverage bottles. Such bottles must be configured to resist high internal pressures of 75 to 100 psi. The sidewall of the bottles can easily withstand such pressure, however, the base structure must be strengthened by deep ribs or grooves to prevent deformation. Besides carbonated beverages, PET is widely used for products such as peanut butter and mayonnaise that are not packaged under pressure.
However, PET has not been used to package products that require moderate packing pressures such as 30 to 50 psi. Such a container would need some base structure reinforcement not found in unpressurized containers but would not need the reinforcement or wall thickness found in carbonated beverage containers. One product requiring such a container is fresh ground coffee. Ground coffee is typically packaged in pressurized cans or vacuum foil pouches, neither of which can be easily and effectively resealed after opening.
Accordingly, it is the object of the present invention to provide a blow molded PET container for packaging products under moderate internal pressures.
It is an advantage of the present invention to provide a container which can be easily resealed after opening.
The blow molded PET container of the present invention includes a base structure reinforced to prevent deformation, particularly roll-out, caused by internal pressure. The base structure includes an annular outer wall extending downwardly and inwardly from the lower end of the container sidewall and an upwardly raised circular inner wall. The inner and outer walls are merged together at their lower ends. Downwardly projecting reinforcing ribs are molded in the lower portion of the outer wall, through the merger of the inner and outer walls and extending into the inner wall. The ribs form rounded bearing surfaces at the lowermost point of the container for supporting the container upright. The merger of the bearing surfaces with the inner wall is formed by two relatively inclined, i.e. non-tangent, surfaces forming interiorly directed corners to stiffen the base structure.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.